textproduct: Rapid City

KEY MESSAGES

- Critical fire weather conditions for portions of northeastern Wyoming through south-central South Dakota this afternoon - Elevated to near-critical fire weather conditions Monday and Tuesday - Gusty winds in excess of 50mph possible later Tuesday behind a cold front - Best chance for accumulating snow this week will be Thursday

DISCUSSION

(This Evening Through Sunday) Issued at 1219 PM MST Sun Feb 15 2026

19z surface analysis had low near Lemmon, SD with a warm front into western NE. Deep mixing behind the front is creating dry air and gusty westerly winds at times. Some thin cirrus floating by. Water vapour matinee portrayed split zonal flow over the plains, but an upper trough is taking shape off the west coast, which will be the main weather maker this week.

Tonight/Monday, upper zonal flow becomes southwest in response to upper trough moving into the western CONUS. Lee trough establishes itself from central MT into eastern CO per thermal ridge. Modest pressure gradient will bring southeasterly winds ahead of the trough and gusty southwesterly winds behind it. Temperatures will be near guidance and 15-25F above normal.

Tuesday, upper trough ejects a compact fast-moving shortwave trough that will reach the Dakotas late in the day, spinning up a low along lee trough that will propel a cold front through the CWA late. Modest QG-forcing will have to work hard to create saturation given antecedent dry air in place, but suspect some QPF will develop with the best lift leading to limited QPF amounts (best chance >0.10" from the Black Hills into northwestern SD). Have dropped prescribed PoPs east/south of the Black Hills per downslope flow behind cold front, which is where strong/gusty northwest winds may occur (40-70% chance >50mph gusts from Wright to Hot Springs to the Badlands). Low confidence in highs Tuesday given cold front timing, but 70F ahead of it is in the realm of possibilities.

Wednesday, weak shortwave ridging in place early with MaxT/s 20-30F less than Tuesday. Later Wednesday/Thursday, stronger shortwave trough rotates into the northern Plains with moderate QG-forcing tapping into an atmosphere closer to saturation. Result will be expanding areas of mostly snow with a couple of inches on the plains and several inches for the Black Hills possible. 40-70% chance of >0.25" QPF for the Black Hills into northwestern SD. Rest of the forecast looks unsettled per northwest flow and a slow warming trend.

AVIATION

(For the 18Z TAFS Through 18Z Monday) Issued At 1015 AM MST Sun Feb 15 2026

VFR conditions will continue through the TAF period.

FIRE WEATHER

Issued At 1219 PM MST Sun Feb 15 2026

Critical fire weather conditions will continue this afternoon with elevated to near critical fire weather conditions for parts of the area Monday and Tuesday. Deep mixing this afternoon will drop minimum relative humidities into the teens from southern Campbell County Wyoming through south-central South Dakota. Gusty west winds will continue, reaching 12 to 25 mph with gusts from 25 to 35 mph at times. Minimum relative humidities Monday and Tuesday will be in the teens/20s over parts of northeastern Wyoming and southwestern South Dakota. Gusty southwest to southeast winds are expected Monday and Tuesday, but quickly switch to the northwest (and quite gusty) behind a cold front later Tuesday. Temperatures will be 15 to 25 degrees above normal this afternoon through Tuesday. A disturbance will bring increasing chances for precipitation late Tuesday through Thursday, which will quell elevated fire weather conditions as temperatures cool and relative humidity increases. Best chance for wetting precipitation will be over the northern Black Hills, and then on the northwestern SD plains Wednesday night/Thursday.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning until 5 PM MST /6 PM CST/ this afternoon for SDZ321-322-325-326-332>335. WY...Red Flag Warning until 5 PM MST this afternoon for WYZ315-317.